The earliest Johnson auto rifles were commercial type semi autos w/detachable magazines, checkered stocks, sporter configuration, etc. They were made in the late 30's by the Taft Pierce Co (sp?) of RI.

They didn't make many. The change to the rotary mag was at the Armys request in '39 for their Ordnance Trials against the Garand. IIRC 7 of those commercial style rifles were built for the trials. The Garand won. It also lost (2nd place) to the Garand in the USMC trials (1940).

Some redesign was done to a more Military looking rifle and a name change to 'Model 1941'
The rotary mag was standard then.
These were Cranston Arms Co, Cranston ,RI mfg rifles.

Holland bought a large number but they never left the docks. The USMC bought a portion of that shipment (they were in cal 30-06) for outfitting Parachute Regiment(s).

The only other contract I've ever heard of was one to Chile during WW2 for around 1k riflesin 7x57 .

After WW2, Johnson Automatics sold out to Winchester in the early 50's. Winchester sold all the parts to Numrich.

Winfield Arms bought most all the remaining Dutch contract rifles from Holland and shipped them to Canada.
Winfield then bought the parts from Numrich.

Winfield built/rebuilt the Dutch rifles and any other J/A rifle they could put together from the parts. Some were 'sporter' models of the Military version. AFAIK all were the rotary mag version.
Some of the Winfield gun building operations probably went on in Canada as well as the USA. The J/A rifles from Winfield pretty much disappeared from the gun magazine ads in the mid 60's.

Melvin Johnson continued to put out different firearms products over the years including the sporterized Mausers, M1 Carbines including his 5.7mm Spitfire version. As I understand it,,those were for the most part made in his custom gunshop at his home in RI.
I don't know if Winchester allowed him to continue use of the J/A name after having sold the business to them. He used 'Johnson Arms Co. New Haven CT' for a time in the 60's.
Perhaps the bbls on some of the Mausers w/ 'J/Automatics' address were mfg'rd earlier. He did make bbls for US Ordnance too.

He did go to work for Winchester after he sold out his J/A Rifle business to them,,that was part of the deal.
He died in the mid 60's I believe.